TOTEM ExperimentTOTEM ExperimentMasterClassesMasterClasses
B. Bressan, G. Latino, and Jan Kaspar (TOTEM Collaboration)
Measurement of dNel /dt in p-p collisions at LHC
SG Meeting, CERN 06/11/14
Results... (after 200 selections “Event-Display Based”)Results... (after 200 selections “Event-Display Based”)
dNel/dt distribution for signal (proper selection)
dNel/dt distribution for background (proper selection)
dNel/dt distribution for signal + background (NO selection)
Analysis performed on data taken on July 2012 @ s = 8 teV
Studying the Studying the SameSame Data Sample: Results from 3 Groups Data Sample: Results from 3 Groups
Nice discussion followed …
Group # 7
Group # 8
Group # 10
B (t=-0.4 GeV2)
tDIP
t-n [1.5–2.5 GeV2]
20.2 0.60 5.023.3 0.51 7.0
22.0 0.54 8.4
25.3 0.48 10.420.1 0.72 4.2
23.6 ± 0.5 0.53 ± 0.01 7.8 ± 0.3
.... Compared to several theoretical predictions...
None of the models really fit
TOTEM Results at s = 7 TeV (ETOTEM Results at s = 7 TeV (Ebb= 3.5 TeV) = 3.5 TeV)
Backup Slid
es
Backup Slid
es
Importance of Angular Importance of Angular Measurements in Measurements in
Scattering Processes Scattering Processes
A historical example: the Rutherford experiment
(e.m. scattering)
ThomsonModel
versus
Rutherford Model
Today we will study the nuclear interaction scattering !
Kinematics of p-p elastic scattering Kinematics of p-p elastic scattering
A typical kinematical variable is t, defined as:
- t p2 2
p = proton momentum = scattering angle
The scattering process can be studied on the x and y “projections”
- tx p2 x2 ; - ty p2 y
2 x= cosy= sin
With: (x, y): hit position at Roman Pot (RP) location
(x*, y*): vertex position at Interaction Point (IP)
(x*,y
*): scattering angle at IP
Proton transport equations for Roman Pots @ 220m:
x = vxx* + Lxx*
y = vyy* + Lyy*
Proton Transport from IP5 to RP LocationProton Transport from IP5 to RP Location
Lx, Ly, vx, vy (optical functions):
- Describe the explicit path of particles through
the magnetic elements as a function of the
particle parameters at IP - Depend on the RP position s along the beam line
- Depend on LHC machine optics configuration
Elastic proton kinematics reconstruction (x
*, y*):
/
/,/
*
***
yy
xxx
xx
Ly
vxxds
dLx
ds
dv
Results Results ““SimilarSimilar”” to Diffraction in Optics to Diffraction in Optics
An example of “wave-particle” duality ?
Anyway: this “behavior” gives the name of diffractive events to these kind of processes in high energy physics
Babinet Principle…
10th December 2013
Pilot activity, Case Western Reserve University, US (K. Cecire)
https://quarknet.i2u2.org/content/totem-masterclass-cwru
•MasterClasses “structure” (10 students)
•First implementation of analysis code only on linux (some limit tech. problems)
•Samples to each group of students for open discussions on the results…
TOTEM MasterClassess Pilot Activity 1TOTEM MasterClassess Pilot Activity 1
What were the best things about the MastercClass today?
•Data analysis, understanding of theory-experimental results correlation
•Videoconference with TOTEM control room
•Studying something not found in a high school physics class program
Would you recommend this MasterClass to other high school?
•Yes!
How can the MasterClass be improved?
•More than 200 events available
•More for the students to analyze in each event (not only "1" or "2”)
TOTEM MasterClassess Pilot Activity 1:TOTEM MasterClassess Pilot Activity 1:Students commentsStudents comments
15th April 2014
Pilot activity, Siena University, Italy (G. Latino)
•MasterClasses (20 students)
•Improved version of the code (previous tech. problems solved)
•Code running on Windows 7 (ROOT package & analysis code stand-alone)
•Samples to each group of students for open discussions on the results…
TOTEM MasterClassess Pilot Activity 2TOTEM MasterClassess Pilot Activity 2
Which aspects of this MasterClass were more interesting?
•Experimental phase and the particle accelerator description
Would you recommend this MasterClass to other high school?
•Yes!
How can the MasterClass be improved?
•More interaction teacher-students
•More time to the experimental phase
•More explanation about the project
TOTEM MasterClassess Pilot Activity 2:TOTEM MasterClassess Pilot Activity 2:Students commentsStudents comments